1. Field of the Invention
The present invention relates to an imaging apparatus capable of detecting an imaging condition with a high accuracy while appropriately displaying an image.
2. Description of the Related Art
Currently, many imaging apparatuses are provided with a live view function that can sequentially display image signals which are continuously read from an image sensor, on a display device such as a liquid crystal display (LCD) monitor disposed on a rear surface or the like of a camera to confirm an image to be captured.
Further, many imaging apparatuses detect an imaging condition such as an object luminance, an in-focus state, and color temperature that appropriately produces a white image based on an output signal read from the image sensor.
However, when an effect of exposure compensation made according to the detected object luminance is to be confirmed using an image displayed by the live view function, an image signal may not be appropriately displayed. This is because the signal read from the image sensor is shifted from a level appropriate to detect the imaging condition.
That is, when exposure compensation is shifted to overexposure, the pixel signals may be saturated. When the exposure compensation is shifted to underexposure, the pixel signals may be collapsed. If the object luminance, an in-focus state, and color temperature that appropriately produces a white image are detected based on the image signal that is not appropriately compensated for detecting the imaging condition, a detection accuracy is reduced.
Japanese Patent Application Laid-open No. 2003-289472 discusses a technology that solves the problem. According to the technology, when the exposure compensation is performed, a signal on which exposure compensation is not performed is read by the image sensor, and a luminance level is adjusted by multiplying a signal from a video random access memory (VRAM) for displaying the image by a gain to display the image.
However, the new technology described above may seriously deteriorate a signal-to-noise (SN) ratio depending on an exposure compensation amount, since the luminance level is adjusted by multiplying the output signal from the VRAM by the gain when the image is displayed.